Measuring polymerization shrinkage of composites utilizing a gas pycnometer
DOI:
https://doi.org/10.14295/bds.2003.v6i3.595Resumen
The objective of this laboratory study was to evaluate the volumetric contraction of five resin composites currently in use. A helium gas pycnometer was used to determine the volume of specimens prior to and after photopolymerization from which total volumetric contraction was obtained. The resin was weighed in an analytic balance and inserted into the pycnometer chamber, the volume of which is known, and hermetically sealed. The volume of the specimen was determined by measuring the pressure change of helium when it was opened up to the expansion chamber. In this study, 15 cycles of pressurizing were repeated for volume determination for each specimen. The arithmetic mean volume was obtained. The final volume was evaluated as done before. The percentage contraction (P) was calculated by: P = 100(SVi - SVf) / SVi, where SV is specific volume and the suffixes i and f indicate measurements before and after polymerization, respectively. The measured volumetric shrinkage ranged from 0.56% for Z250 (3M-ESPE) to 3.26% for P60 (3M-ESPE). The gas pycnometry is a promising method and its mechanism should be more explored for investigating dental materials.Descargas
Descargas
Publicado
Cómo citar
Número
Sección
Licencia
Brazilian Dental Science uses the Creative Commons (CC-BY 4.0) license, thus preserving the integrity of articles in an open access environment. The journal allows the author to retain publishing rights without restrictions.
=================
COPYRIGHT TRANSFER AND RESPONSIBILITY STATEMENT
(PDF)
For all articles published in the BDS journal, copyright is retained by the authors. Articles are licensed under an open-access Creative Commons CC BY 4.0 license, meaning that anyone may download and read the paper for free. In addition, the article may be reused and quoted, provided that the original published version is cited. These conditions allow for maximum use and exposure of the work while ensuring that the authors receive proper credit. All metadata associated with published articles is released under the Creative Commons CC0 Universal Public Domain Dedication.
Before the submission, authors must obtain permission to reproduce any published material (figures, schemes, tables, or any extract of a text) that does not fall into the public domain or for which they do not hold the copyright. Permission should be requested by the authors from the copyright holder (usually the Publisher, please refer to the imprint of the individual publications to identify the copyright holder).
The authors hereby attest that the study is original and does not present manipulated data, fraud, or plagiarism. All names listed made a significant scientific contribution to the study, are aware of the presented data, and agree with the final version of the manuscript. They assume complete responsibility for the ethical aspects of the study.
This text must be printed and signed by all authors. The scanned version should be submitted as supplemental file during the submission process.
